From cd9ea11454f50855facef7875c9d872ddd4dc662 Mon Sep 17 00:00:00 2001 From: Adrien Mazarguil Date: Fri, 24 Jun 2016 15:18:03 +0200 Subject: [PATCH] net/mlx5: make Rx queue reinitialization safer The primary purpose of rxq_rehash() function is to stop and restart reception on a queue after re-posting buffers. This may fail if the array that temporarily stores existing buffers for reuse cannot be allocated. Update rxq_rehash() to work on the target queue directly (not through a template copy) and avoid this allocation. rxq_alloc_elts() is modified accordingly to take buffers from an existing queue directly and update their refcount. Unlike rxq_rehash(), rxq_setup() must work on a temporary structure but should not allocate new mbufs from the pool while reinitializing an existing queue. This is achieved by using the refcount-aware rxq_alloc_elts() before overwriting queue data. Signed-off-by: Adrien Mazarguil Signed-off-by: Vasily Philipov --- drivers/net/mlx5/mlx5_rxq.c | 83 ++++++++++++++++++------------------- 1 file changed, 41 insertions(+), 42 deletions(-) diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c index fbf14faaab..b2ddd0d357 100644 --- a/drivers/net/mlx5/mlx5_rxq.c +++ b/drivers/net/mlx5/mlx5_rxq.c @@ -642,7 +642,7 @@ priv_rehash_flows(struct priv *priv) */ static int rxq_alloc_elts(struct rxq_ctrl *rxq_ctrl, unsigned int elts_n, - struct rte_mbuf **pool) + struct rte_mbuf *(*pool)[]) { unsigned int i; int ret = 0; @@ -654,9 +654,10 @@ rxq_alloc_elts(struct rxq_ctrl *rxq_ctrl, unsigned int elts_n, &(*rxq_ctrl->rxq.wqes)[i]; if (pool != NULL) { - buf = *(pool++); + buf = (*pool)[i]; assert(buf != NULL); rte_pktmbuf_reset(buf); + rte_pktmbuf_refcnt_update(buf, 1); } else buf = rte_pktmbuf_alloc(rxq_ctrl->rxq.mp); if (buf == NULL) { @@ -781,7 +782,7 @@ rxq_cleanup(struct rxq_ctrl *rxq_ctrl) } /** - * Reconfigure a RX queue with new parameters. + * Reconfigure RX queue buffers. * * rxq_rehash() does not allocate mbufs, which, if not done from the right * thread (such as a control thread), may corrupt the pool. @@ -798,67 +799,48 @@ rxq_cleanup(struct rxq_ctrl *rxq_ctrl) int rxq_rehash(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl) { - struct rxq_ctrl tmpl = *rxq_ctrl; - unsigned int mbuf_n; - unsigned int desc_n; - struct rte_mbuf **pool; - unsigned int i, k; + unsigned int elts_n = rxq_ctrl->rxq.elts_n; + unsigned int i; struct ibv_exp_wq_attr mod; int err; DEBUG("%p: rehashing queue %p", (void *)dev, (void *)rxq_ctrl); - /* Number of descriptors and mbufs currently allocated. */ - desc_n = tmpl.rxq.elts_n; - mbuf_n = desc_n; /* From now on, any failure will render the queue unusable. * Reinitialize WQ. */ mod = (struct ibv_exp_wq_attr){ .attr_mask = IBV_EXP_WQ_ATTR_STATE, .wq_state = IBV_EXP_WQS_RESET, }; - err = ibv_exp_modify_wq(tmpl.wq, &mod); + err = ibv_exp_modify_wq(rxq_ctrl->wq, &mod); if (err) { ERROR("%p: cannot reset WQ: %s", (void *)dev, strerror(err)); assert(err > 0); return err; } - /* Allocate pool. */ - pool = rte_malloc(__func__, (mbuf_n * sizeof(*pool)), 0); - if (pool == NULL) { - ERROR("%p: cannot allocate memory", (void *)dev); - return ENOBUFS; - } /* Snatch mbufs from original queue. */ - k = 0; - for (i = 0; (i != desc_n); ++i) - pool[k++] = (*rxq_ctrl->rxq.elts)[i]; - assert(k == mbuf_n); - rte_free(pool); + claim_zero(rxq_alloc_elts(rxq_ctrl, elts_n, rxq_ctrl->rxq.elts)); + for (i = 0; i != elts_n; ++i) { + struct rte_mbuf *buf = (*rxq_ctrl->rxq.elts)[i]; + + assert(rte_mbuf_refcnt_read(buf) == 2); + rte_pktmbuf_free_seg(buf); + } /* Change queue state to ready. */ mod = (struct ibv_exp_wq_attr){ .attr_mask = IBV_EXP_WQ_ATTR_STATE, .wq_state = IBV_EXP_WQS_RDY, }; - err = ibv_exp_modify_wq(tmpl.wq, &mod); + err = ibv_exp_modify_wq(rxq_ctrl->wq, &mod); if (err) { ERROR("%p: WQ state to IBV_EXP_WQS_RDY failed: %s", (void *)dev, strerror(err)); goto error; } - /* Post SGEs. */ - err = rxq_alloc_elts(&tmpl, desc_n, pool); - if (err) { - ERROR("%p: cannot reallocate WRs, aborting", (void *)dev); - rte_free(pool); - assert(err > 0); - return err; - } /* Update doorbell counter. */ - rxq_ctrl->rxq.rq_ci = desc_n; + rxq_ctrl->rxq.rq_ci = elts_n; rte_wmb(); *rxq_ctrl->rxq.rq_db = htonl(rxq_ctrl->rxq.rq_ci); error: - *rxq_ctrl = tmpl; assert(err >= 0); return err; } @@ -868,24 +850,26 @@ rxq_rehash(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl) * * @param tmpl * Pointer to RX queue control template. - * @param rxq_ctrl - * Pointer to RX queue control. * * @return * 0 on success, errno value on failure. */ static inline int -rxq_setup(struct rxq_ctrl *tmpl, struct rxq_ctrl *rxq_ctrl) +rxq_setup(struct rxq_ctrl *tmpl) { struct ibv_cq *ibcq = tmpl->cq; struct mlx5_cq *cq = to_mxxx(cq, cq); struct mlx5_rwq *rwq = container_of(tmpl->wq, struct mlx5_rwq, wq); + struct rte_mbuf *(*elts)[tmpl->rxq.elts_n] = + rte_calloc_socket("RXQ", 1, sizeof(*elts), 0, tmpl->socket); if (cq->cqe_sz != RTE_CACHE_LINE_SIZE) { ERROR("Wrong MLX5_CQE_SIZE environment variable value: " "it should be set to %u", RTE_CACHE_LINE_SIZE); return EINVAL; } + if (elts == NULL) + return ENOMEM; tmpl->rxq.rq_db = rwq->rq.db; tmpl->rxq.cqe_n = ibcq->cqe + 1; tmpl->rxq.cq_ci = 0; @@ -897,9 +881,7 @@ rxq_setup(struct rxq_ctrl *tmpl, struct rxq_ctrl *rxq_ctrl) tmpl->rxq.cqes = (volatile struct mlx5_cqe (*)[]) (uintptr_t)cq->active_buf->buf; - tmpl->rxq.elts = - (struct rte_mbuf *(*)[tmpl->rxq.elts_n]) - ((uintptr_t)rxq_ctrl + sizeof(*rxq_ctrl)); + tmpl->rxq.elts = elts; return 0; } @@ -947,6 +929,7 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl, enum ibv_exp_query_intf_status status; unsigned int mb_len = rte_pktmbuf_data_room_size(mp); unsigned int cqe_n = desc - 1; + struct rte_mbuf *(*elts)[desc] = NULL; int ret = 0; (void)conf; /* Thresholds configuration (ignored). */ @@ -1104,13 +1087,19 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl, (void *)dev, strerror(ret)); goto error; } - ret = rxq_setup(&tmpl, rxq_ctrl); + ret = rxq_setup(&tmpl); if (ret) { ERROR("%p: cannot initialize RX queue structure: %s", (void *)dev, strerror(ret)); goto error; } - ret = rxq_alloc_elts(&tmpl, desc, NULL); + /* Reuse buffers from original queue if possible. */ + if (rxq_ctrl->rxq.elts_n) { + assert(rxq_ctrl->rxq.elts_n == desc); + assert(rxq_ctrl->rxq.elts != tmpl.rxq.elts); + ret = rxq_alloc_elts(&tmpl, desc, rxq_ctrl->rxq.elts); + } else + ret = rxq_alloc_elts(&tmpl, desc, NULL); if (ret) { ERROR("%p: RXQ allocation failed: %s", (void *)dev, strerror(ret)); @@ -1119,6 +1108,14 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl, /* Clean up rxq in case we're reinitializing it. */ DEBUG("%p: cleaning-up old rxq just in case", (void *)rxq_ctrl); rxq_cleanup(rxq_ctrl); + /* Move mbuf pointers to dedicated storage area in RX queue. */ + elts = (void *)(rxq_ctrl + 1); + rte_memcpy(elts, tmpl.rxq.elts, sizeof(*elts)); +#ifndef NDEBUG + memset(tmpl.rxq.elts, 0x55, sizeof(*elts)); +#endif + rte_free(tmpl.rxq.elts); + tmpl.rxq.elts = elts; *rxq_ctrl = tmpl; /* Update doorbell counter. */ rxq_ctrl->rxq.rq_ci = desc; @@ -1128,7 +1125,9 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl, assert(ret == 0); return 0; error: + elts = tmpl.rxq.elts; rxq_cleanup(&tmpl); + rte_free(elts); assert(ret > 0); return ret; }